Something that could have been told in a more concise way but is dragged out because the teller doesn't know how to tell a story. It's a play on the annoying clarifier, "Long story short," people use to sum up a digression, which really never seems to be that short anyway. So instead you say the opposite.

So I was walking into the store the other day, I wanted to get some aspirin because I had this massive headache and I walked down aisle four but they only had Tylenol but that doesn't work and I went to the counter and short story long this guy was holding up the store!